Democratizing access to the best data on religion since 1997

Frequently Asked Questions


How do I cite the ARDA if I use the data for a publication (newspaper article, journal article, research/term paper, book, etc.)?

When using ARDA data in publications and presentations, the author should acknowledge the Association of Religion Data Archives and the original collector(s) of the data (e.g., The data were downloaded from the Association of Religion Data Archives,, and were collected by [name of principal investigator(s)]).

Who are you and who funds this?

The ARDA is based in the Department of Sociology at The Pennsylvania State University. Our goal is to preserve and provide access to high-quality data on religion in the United States and abroad. We are funded by the Lilly Endowment and the John Templeton Foundation.

Do you have any data on the number of members of a particular denomination in a particular state or county?

The United States Census has not collected information on religion since 1936. The closest thing to a "religious census" is The Church and Church Membership Studies (after 1990 this has been called the Religious Congregations and Membership Study or RCMS). These studies are done about every 10 years and they report the number of churches, number of members, and number of adherents per participating denomination at both the state and county level. The ARDA features this data in our map and report features. We also have most of the data available for download in the data archive.

Are you the ones who collected all of this data?

No (with an exception). The ARDA is primarily an archive, meaning that we store the data that other researchers have collected. You can find information on exactly who collected a particular data collection in the File Summary portion after selecting a data collection to examine in the Data Archive.  The only exception to this is some of the data in the International Data where ARDA staff have created measures of religious freedom and regulation based on the U.S. State Department's Religious Freedom Reports. For more information on this, see Grim and Finke 2006 in the Interdisciplinary Journal for Research on Religion.

Why do you have data on some religious groups but not others?

This is due to a combination of factors. First, the ARDA relies on donations of data from researchers. For various reasons some data cannot be donated to the ARDA even though it would make a valuable addition to the archive. Second, some groups are only now beginning to gain attention from researchers that are interested in gathering quantitative data. Third, some groups are difficult to gather quantitative data on even if a researcher is interested in them due to various reasons (e.g. the group's structure is not very organized, the group does not keep records that would be useful to researchers, etc.).

If you know of data that should be added to our archive, please send us the name of the data collection and any contact information you might have.

In your Maps & Reports, is an "adherent" the same thing as a "member"?

Religious groups vary in their standards for declaring people "members." Some churches count infants as church members. Others reserve membership for those who have given a testimony of faith, completed designated training, and/or attained a specific age. To get a standardized rate across denominations, adherents are used. Using adherents instead of members adjusts for groups that do not give full membership status to children. The file description page of the Church and Church Membership data collections contains information about how adherents were calculated for groups that only kept records of full members.

Do you have a list of members for {insert church name} in {insert city\state}? For example, do you have lists of names & addresses of active members of all Assembly of God churches in the Atlanta area?

We do not have this sort of information. Most of our data are from surveys where names and addresses are deleted to preserve confidentiality.

Why do some of the data collections have the option of being downloaded in Microsoft Excel format and others do not?

Prior to 2010 Excel limited data collections to 250 variables and thus, Excel downloads for larger data collections were not created. Beginning in 2016, however, we began formatting all files for the newer version of Excel without these limits. If you would like a specific file in Excel format, please contact us and we can convert it for you.

How does the ARDA classify religious groups into categories such as "mainline" or "evangelical"? How should I classify groups that are not included in the ARDA's data?

Classifying denominations can certainly be tricky. We relied on several sources. We began with an article co-authored by Brian Steensland, Jerry Park, Mark Regnerus, Lynn Robinson, Bradford Wilcox, and Robert Woodberry entitled "The Measure of American Religion: Toward Improving the State of the Art," and published in Social Forces (2000, 79: 291-318). They justified the major categories we used and classified many of the groups in the RCMS collection. When denominations were not included in their classification, we classified the groups based on information given in J. Gordon Melton's Encyclopedia of American Religions (6th edition) and Frank S. Mead and Samuel S. Hill's Handbook of Denominations in the United States (10th edition).

For in-depth information on how the ARDA classifies religious groups, download the ARDA Religion Classification Guide.

What if I am not familiar with statistics?

In order for our site to be helpful, we have created an online analysis feature. Click on the Analyze Results link(s) for variable(s) of interest after selecting a data collection codebook in the Data Archive section of the website.  This will automatically create a series of tables and graphs for you based on that variable.

What if I need more information than the online analysis gives me?

You can download all files in the "Data Archive" in SPSS, Stata, Excel, or ASCII format.   To download files, select any data collection in the Data Archive. Then click on the "Download" option.

How do I submit data to the ARDA?

If you know of a data collection that should be included in the Association of Religion Data Archives, please contact us using the addresses or phone number given below. If you would like to submit a data collection, please complete the Submission Form and send the data file, appropriate support material, and a completed submission form (including the authorization form) to our office. Click here for a copy of the submission form in Microsoft Word format.

Will the ARDA staff help me with my research?

Our staff may be able to direct you to appropriate files, but they will not perform statistical analysis or supply answers to questions other than brief descriptions of the files.

How do I manage my email newsletter subscription?

Please visit our Subscribe page to sign up or unsubscribe.

How do I contact the ARDA staff?

E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Phone: 814-865-6258
Fax: 814-863-7216




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